diff --git a/src/Altinn.App.Core/Internal/Expressions/ExpressionEvaluator.cs b/src/Altinn.App.Core/Internal/Expressions/ExpressionEvaluator.cs
index 1ec0979d4..9eb3b037b 100644
--- a/src/Altinn.App.Core/Internal/Expressions/ExpressionEvaluator.cs
+++ b/src/Altinn.App.Core/Internal/Expressions/ExpressionEvaluator.cs
@@ -1,4 +1,5 @@
 using System.Globalization;
+using System.Text.Json;
 using System.Text.RegularExpressions;
 using Altinn.App.Core.Models.Expressions;
 using Altinn.App.Core.Models.Layout.Components;
@@ -473,54 +474,39 @@ bool ab
         return a >= b; // Actual implementation
     }
 
-    private static string? ToStringForEquals(object? value)
-    {
-        if (value is null)
-        {
-            return null;
-        }
-
-        if (value is bool bvalue)
-        {
-            return bvalue ? "true" : "false";
-        }
-
-        if (value is string svalue)
+    internal static string? ToStringForEquals(object? value) =>
+        value switch
         {
+            null => null,
+            bool bValue => bValue ? "true" : "false",
             // Special case for "TruE" to be equal to true
-            if ("true".Equals(svalue, StringComparison.OrdinalIgnoreCase))
-            {
-                return "true";
-            }
-            else if ("false".Equals(svalue, StringComparison.OrdinalIgnoreCase))
-            {
-                return "false";
-            }
-            else if ("null".Equals(svalue, StringComparison.OrdinalIgnoreCase))
-            {
-                return null;
-            }
-
-            return svalue;
-        }
-        else if (value is decimal decvalue)
-        {
-            return decvalue.ToString(CultureInfo.InvariantCulture);
-        }
-        else if (value is double doubvalue)
-        {
-            return doubvalue.ToString(CultureInfo.InvariantCulture);
-        }
-        else if (value is int intvalue)
-        {
-            return intvalue.ToString(CultureInfo.InvariantCulture);
-        }
-
-        //TODO: consider accepting more types that might be used in model (eg Datetime)
-        throw new NotImplementedException();
-    }
+            string sValue when "true".Equals(sValue, StringComparison.OrdinalIgnoreCase) => "true",
+            string sValue when "false".Equals(sValue, StringComparison.OrdinalIgnoreCase) => "false",
+            string sValue when "null".Equals(sValue, StringComparison.OrdinalIgnoreCase) => null,
+            string sValue => sValue,
+            decimal decValue => decValue.ToString(CultureInfo.InvariantCulture),
+            double doubleValue => doubleValue.ToString(CultureInfo.InvariantCulture),
+            float floatValue => floatValue.ToString(CultureInfo.InvariantCulture),
+            int intValue => intValue.ToString(CultureInfo.InvariantCulture),
+            uint uintValue => uintValue.ToString(CultureInfo.InvariantCulture),
+            short shortValue => shortValue.ToString(CultureInfo.InvariantCulture),
+            ushort ushortValue => ushortValue.ToString(CultureInfo.InvariantCulture),
+            long longValue => longValue.ToString(CultureInfo.InvariantCulture),
+            ulong ulongValue => ulongValue.ToString(CultureInfo.InvariantCulture),
+            byte byteValue => byteValue.ToString(CultureInfo.InvariantCulture),
+            sbyte sbyteValue => sbyteValue.ToString(CultureInfo.InvariantCulture),
+            // BigInteger bigIntValue => bigIntValue.ToString(CultureInfo.InvariantCulture), // Big integer not supported in json
+            DateTime dtValue => JsonSerializer.Serialize(dtValue),
+            DateOnly dateValue => JsonSerializer.Serialize(dateValue),
+            TimeOnly timeValue => JsonSerializer.Serialize(timeValue),
+            //TODO: Consider having JsonSerializer as a fallback for everything (including arrays and objects)
+            _
+                => throw new NotImplementedException(
+                    $"ToStringForEquals not implemented for type {value.GetType().Name}"
+                )
+        };
 
-    private static bool? EqualsImplementation(object?[] args)
+    internal static bool? EqualsImplementation(object?[] args)
     {
         if (args.Length != 2)
         {
diff --git a/test/Altinn.App.Core.Tests/LayoutExpressions/ExpressionEvaluatorTests/EqualsTests.cs b/test/Altinn.App.Core.Tests/LayoutExpressions/ExpressionEvaluatorTests/EqualsTests.cs
new file mode 100644
index 000000000..275bba8d1
--- /dev/null
+++ b/test/Altinn.App.Core.Tests/LayoutExpressions/ExpressionEvaluatorTests/EqualsTests.cs
@@ -0,0 +1,99 @@
+using System.Numerics;
+using System.Text.Json;
+using Altinn.App.Core.Internal.Expressions;
+using Xunit.Abstractions;
+
+namespace Altinn.App.Core.Tests.LayoutExpressions.ExpressionEvaluatorTests;
+
+public class EqualTests(ITestOutputHelper outputHelper)
+{
+    public static TheoryData<object> GetNumericTestData(double value) =>
+        new()
+        {
+            value,
+            (byte)value,
+            (sbyte)value,
+            (short)value,
+            (ushort)value,
+            (int)value,
+            (uint)value,
+            (long)value,
+            (ulong)value,
+            (float)value,
+            (decimal)value,
+            // (BigInteger)value, // Not supported by JsonSerializer
+        };
+
+    public static TheoryData<object> GetExoticTypes =>
+        new()
+        {
+            "123",
+            true,
+            false,
+            "",
+            DateTime.Now,
+            DateOnly.FromDateTime(DateTime.Now),
+            TimeOnly.FromDateTime(DateTime.Now),
+        };
+
+    [Theory]
+    [MemberData(nameof(GetNumericTestData), 123.0)]
+    [MemberData(nameof(GetNumericTestData), 0.5)]
+    [MemberData(nameof(GetNumericTestData), -123.0)]
+    [MemberData(nameof(GetExoticTypes))]
+    public void ToStringForEquals_AgreesWithJsonSerializer(object? value)
+    {
+        outputHelper.WriteLine($"Object of type {value?.GetType().FullName ?? "null"}:");
+        outputHelper.WriteLine($"   value:{value}");
+        outputHelper.WriteLine($"   json: {JsonSerializer.Serialize(value)}");
+        // Verify that the EqualsToString method returns the same value as the JsonSerializer.
+        var json = value is string ? value : JsonSerializer.Serialize(value);
+        var toStringForEquals = ExpressionEvaluator.ToStringForEquals(value);
+        Assert.Equal(json, toStringForEquals);
+    }
+
+    public static TheoryData<object> GetNonsenseValues =>
+        new()
+        {
+            new BigInteger(123), // Not supported by JsonSerializer, but might make sense to support
+            new object[] { 1, 2, 3 },
+            new object(),
+            new
+            {
+                A = 1,
+                B = 2,
+                C = 3
+            },
+            new byte[] { 0x01, 0x02, 0x03 },
+        };
+
+    [Theory]
+    [MemberData(nameof(GetNonsenseValues))]
+    public void ToStringForEquals_NonsenseTypes_ThrowsException(object? value)
+    {
+        outputHelper.WriteLine($"Object of type {value?.GetType().FullName ?? "null"}:");
+        outputHelper.WriteLine($"   value:{value}");
+        outputHelper.WriteLine($"   json: {JsonSerializer.Serialize(value)}");
+        // Verify that the EqualsToString method throws an exception for unsupported types.
+        Assert.Throws<NotImplementedException>(() => ExpressionEvaluator.ToStringForEquals(value));
+    }
+
+    [Theory]
+    [InlineData(null, null)]
+    [InlineData("null", null)]
+    [InlineData("Null", null)]
+    [InlineData("true", "true")]
+    [InlineData("trUe", "true")]
+    [InlineData("True", "true")]
+    [InlineData(true, "true")]
+    [InlineData("false", "false")]
+    [InlineData("False", "false")]
+    [InlineData("falSe", "false")]
+    [InlineData(false, "false")]
+    public void ToStringForEquals_SpecialCases(object? value, string? expected)
+    {
+        // Verify that the EqualsToString method returns the expected value for special cases.
+        var toStringForEquals = ExpressionEvaluator.ToStringForEquals(value);
+        Assert.Equal(expected, toStringForEquals);
+    }
+}